CN-224203821-U - Pixel circuit and electronic device including the same

Abstract

A pixel circuit and an electronic device including the same are provided. The pixel circuit includes a light emitting element, a constant current generation circuit, and a pulse width modulation circuit. The constant current generation circuit includes a seventh transistor including a gate electrode connected to the fourth node, a first electrode configured to receive a second high power supply voltage, and a second electrode connected to the fifth node, an eighth transistor including a gate electrode configured to receive a second write gate signal, a first electrode to receive a data voltage, and a second electrode connected to the sixth node, and a second capacitor including a first electrode connected to the sixth node and a second electrode connected to the fourth node. The pixel circuit can improve image quality.

Inventors

• Jin Guixuan
• JIN DONGYOU
• LI SHIXIAN

Assignees

• 三星显示有限公司

Dates

Publication Date

20260505

Application Date

20250328

Priority Date

20240502

Claims (19)

1. 1. A pixel circuit, the pixel circuit comprising: A light emitting element; a constant current generation circuit configured to generate a data voltage, a second high power supply voltage, and a low power supply voltage based on a constant current of the data voltage to generate a fixed driving current to supply the light emitting element with the fixed driving current, and A pulse width modulation circuit configured to control a generation time of the fixed driving current based on a pulse width modulation data voltage of the data voltage, a sweep voltage, a first high power supply voltage different from the second high power supply voltage, and the low power supply voltage, Wherein the pulse width modulation circuit comprises a first transistor including a gate electrode connected to a first node, a first electrode connected to a second node, and a second electrode connected to a third node, a second transistor including a gate electrode configured to receive a first write gate signal, a first electrode configured to receive the data voltage, and a second electrode connected to the second node, and a first capacitor including a first electrode configured to receive the sweep voltage, and a second electrode connected to the first node, and The constant current generation circuit includes a seventh transistor including a gate electrode connected to a fourth node, a first electrode configured to receive the second high power supply voltage, and a second electrode connected to a fifth node, an eighth transistor including a gate electrode configured to receive a second write gate signal, a first electrode configured to receive the data voltage, and a second electrode connected to a sixth node, and a second capacitor including a first electrode connected to the sixth node and a second electrode connected to the fourth node.
2. 2. The pixel circuit according to claim 1, wherein the constant current generation circuit further comprises: A third capacitor including a first electrode configured to receive the second high supply voltage and a second electrode connected to the sixth node.
3. 3. The pixel circuit according to claim 2, wherein the constant current generation circuit further comprises: A ninth transistor includes a gate electrode configured to receive a compensated gate signal, a first electrode connected to the fifth node, and a second electrode connected to the fourth node.
4. 4. A pixel circuit according to claim 3, wherein the constant current generation circuit further comprises: An eleventh transistor includes a gate electrode configured to receive the second initialization gate signal, a first electrode configured to receive an initialization voltage, and a second electrode connected to the fourth node.
5. 5. The pixel circuit according to claim 4, wherein the light emitting element includes an anode connected to the constant current generation circuit and a cathode configured to receive the low power supply voltage, and The constant current generation circuit further includes a twelfth transistor including a gate electrode configured to receive an anode initialization gate signal, a first electrode configured to receive an anode initialization voltage, and a second electrode connected to the anode of the light emitting element.
6. 6. The pixel circuit according to claim 5, wherein the seventh transistor and the twelfth transistor are P-type transistors, and wherein the eighth transistor, the ninth transistor, and the eleventh transistor are N-type transistors.
7. 7. The pixel circuit according to claim 5, wherein the seventh transistor to the ninth transistor, the eleventh transistor, and the twelfth transistor are P-type transistors.
8. 8. The pixel circuit of claim 5, wherein the compensation gate signal, the second write gate signal, and the second initialization gate signal are global scan signals.
9. 9. The pixel circuit according to claim 5, wherein the constant current generation circuit further comprises: a tenth transistor connected between the fifth node and the anode of the light emitting element, and configured to be turned on in response to an emission signal.
10. 10. The pixel circuit according to claim 5, wherein the constant current generation circuit further comprises: A tenth transistor configured to receive the second high power supply voltage and to be connected to the first electrode of the seventh transistor, and configured to be turned on in response to a transmission signal.
11. 11. The pixel circuit of claim 1, wherein the pulse width modulation circuit further comprises: A third transistor including a gate electrode configured to receive the first write gate signal, a first electrode connected to the third node, and a second electrode connected to the first node.
12. 12. The pixel circuit of claim 11, wherein the pulse width modulation circuit further comprises: A sixth transistor includes a gate electrode configured to receive the first initialization gate signal, a first electrode configured to receive an initialization voltage, and a second electrode connected to the first node.
13. 13. The pixel circuit of claim 12, wherein the pulse width modulation circuit further comprises: A fourth transistor including a gate electrode configured to receive a transmission signal, a first electrode configured to receive the first high power supply voltage, and a second electrode connected to the second node, and A fifth transistor including a gate electrode configured to receive the emission signal, a first electrode connected to the third node, and a second electrode connected to the fourth node.
14. 14. The pixel circuit according to claim 13, wherein the first transistor, the fourth transistor, and the fifth transistor are P-type transistors, and the second transistor, the third transistor, and the sixth transistor are N-type transistors.
15. 15. The pixel circuit according to claim 13, wherein the first transistor to the sixth transistor are P-type transistors.
16. 16. The pixel circuit of claim 13, wherein the first write gate signal is a progressive scan signal and the second write gate signal, the first initialization gate signal, and the emission signal are global scan signals.
17. 17. The pixel circuit of claim 1, wherein the second high supply voltage is lower than the first high supply voltage.
18. 18. An electronic device comprising a display device, the display device comprising: a display panel including pixel circuits, and A display panel driver configured to drive the display panel, Wherein the pixel circuit includes: A light emitting element; a constant current generation circuit configured to generate a data voltage, a second high power supply voltage, and a low power supply voltage based on a constant current of the data voltage to generate a fixed driving current to supply the light emitting element with the fixed driving current, and A pulse width modulation circuit configured to control a generation time of the fixed driving current based on a pulse width modulation data voltage of the data voltage, a sweep voltage, a first high power supply voltage different from the second high power supply voltage, and the low power supply voltage, Wherein the pulse width modulation circuit comprises a first transistor including a gate electrode connected to a first node, a first electrode connected to a second node, and a second electrode connected to a third node, a second transistor including a gate electrode configured to receive a first write gate signal, a first electrode configured to receive the data voltage, and a second electrode connected to the second node, and a first capacitor including a first electrode configured to receive the sweep voltage, and a second electrode connected to the first node, and The constant current generation circuit includes a seventh transistor including a gate electrode connected to a fourth node, a first electrode configured to receive the second high power supply voltage, and a second electrode connected to a fifth node, and an eighth transistor including a gate electrode configured to receive a second write gate signal, a first electrode configured to receive the data voltage, and a second electrode connected to a sixth node.
19. 19. The electronic device of claim 18, wherein the electronic device comprises a mobile phone, a video phone, a smart tablet, a smart phone, a tablet PC, a car navigation system, a computer monitor, a laptop computer, or a head mounted display device.

Description

Pixel circuit and electronic device including the same Technical Field The present disclosure relates to a pixel circuit and an electronic device including the same. More particularly, the present disclosure relates to a pixel circuit for driving a light emitting element using a Pulse Width Modulation (PWM) method and an electronic device including the pixel circuit. Background Methods of driving light emitting elements such as micro light emitting diodes (uLED), organic Light Emitting Diodes (OLEDs), and the like may include a Pulse Amplitude Modulation (PAM) method and a Pulse Width Modulation (PWM) method. In the PAM method, the amount (or amplitude) of the driving current supplied to the light emitting element may be adjusted to represent brightness. On the other hand, in the PWM method, the time (or pulse width) of the driving current supplied to the light emitting element may be adjusted to represent the luminance. The light emitting element such as a micro light emitting diode may have a characteristic in which the wavelength of light is shifted according to the amount of driving current. Therefore, when a light emitting element such as a micro light emitting diode is driven by the PAM method, a color shift phenomenon may be generated and an image may be distorted. Disclosure of utility model It is an object of the utility model to provide a pixel circuit for providing improved image quality. The utility model aims to provide an electronic device comprising the pixel circuit. In one or more embodiments, a pixel circuit includes a light emitting element, a Constant Current Generation (CCG) circuit configured to generate a fixed driving current based on a CCG data voltage of a data voltage, a second high power supply voltage, and a low power supply voltage to supply the fixed driving current to the light emitting element, and a Pulse Width Modulation (PWM) circuit configured to control a generation time of the fixed driving current based on a PWM data voltage of the data voltage, a sweep voltage, and a first high power supply voltage and a low power supply voltage different from the second high power supply voltage. The PWM circuit includes a first transistor including a gate electrode connected to a first node, a first electrode connected to a second node, and a second electrode connected to a third node, a second transistor including a gate electrode configured to receive a first write gate signal, a first electrode configured to receive a data voltage, and a second electrode connected to the second node, and a first capacitor including a first electrode configured to receive a sweep voltage, and a second electrode connected to the first node. The CCG circuit includes a seventh transistor including a gate electrode connected to the fourth node, a first electrode configured to receive a second high power supply voltage, and a second electrode connected to the fifth node, an eighth transistor including a gate electrode configured to receive a second write gate signal, a first electrode configured to receive a data voltage, and a second electrode connected to the sixth node, and a second capacitor including a first electrode connected to the sixth node and a second electrode connected to the fourth node. In one or more embodiments, the CCG circuit may further include a third capacitor including a first electrode configured to receive the second high supply voltage and a second electrode connected to the sixth node. In one or more embodiments, the CCG circuit may further include a ninth transistor including a gate electrode configured to receive the compensated gate signal, a first electrode connected to the fifth node, and a second electrode connected to the fourth node. In one or more embodiments, the CCG circuit may further include an eleventh transistor including a gate electrode configured to receive the second initialization gate signal, a first electrode configured to receive the initialization voltage, and a second electrode connected to the fourth node. In one or more embodiments, the light emitting element may include an anode connected to the CCG circuit and a cathode configured to receive a low supply voltage. The CCG circuit may further include a twelfth transistor including a gate electrode configured to receive the anode initialization gate signal, a first electrode configured to receive the anode initialization voltage, and a second electrode connected to the anode of the light emitting element. In one or more embodiments, the seventh transistor and the twelfth transistor are P-type transistors, and the eighth transistor, the ninth transistor, and the eleventh transistor are N-type transistors. In one or more embodiments, the seventh to ninth transistors, the eleventh transistor, and the twelfth transistor may be P-type transistors. In one or more embodiments, the compensation gate signal, the second write gate signal, and the second initialization gate signal may be global scan signals.